This invention relates to procedures and equipment for profiling and jointing of pipes, and relates more particularly but not exclusively to methods and apparatus for the shaping and/or expansion and/or conjoining of tubular casings in wells.
In the hydrocarbon exploration and production industry there is a requirement to deploy tubular casings in relatively narrow-bore wells, and to expand the deployed casing in situ. The casing may require to be expanded throughout its length in order to line a bore drilled through geological material; the casing may additionally or alternatively require to be expanded at one end where it overlaps and lies concentrically within another length of previously deployed casing in order to form a swaged joint between the two lengths of casing. Proposals have been made that a slotted metal tube be expanded by mechanically pulling a mandrel through the tube, and that a solid-walled steel tube be expanded by hydraulically pushing a part-conical ceramic plunger through the tube. In both of these proposals, very high longitudinal forces would be exerted throughout the length of the tubing, which accordingly would require to be anchored at one end. Where mechanical pulling is to be employed, the pulling force would require to be exerted through a drillstring (in relatively large diameter wells) or through coiled tubing (in relatively small diameter wells). The necessary force would become harder to apply as the well became more deviated (i.e. more non-vertical), and in any event, coiled tubing may not tolerate high longitudinal forces. Where hydraulic pushing is to be employed, the required pressure may be hazardously high, and in any event the downhole system would require to be pressure-tight and substantially leak-free. (This would preclude the use of a hydraulically pushed mandrel for the expansion of slotted tubes). The use of a fixed-diameter mandrel or plug would make it impracticable or impossible to control or to vary post-deformation diameter after the start of the expansion procedure.
It is therefore an object of the invention to provide new and improved procedures and equipment for the profiling or jointing of pipes or other hollow tubular articles, which obviate or mitigate at least some of the disadvantages of the prior art.
In the following specification and claims, references to a xe2x80x9cpipexe2x80x9d are to be taken as references to a hollow tubular pipe and to other forms of hollow tubular article, and references to xe2x80x9cprofilingxe2x80x9d are to be taken as comprising alteration of shape and/or dimension(s) which alteration preferably takes place substantially without removal of material.
According to a first aspect of the present invention there is provided a profiling method for profiling a pipe or other hollow tubular article, the profiling method comprising the steps of applying a roller means to a part of the pipe bore selected to be profiled, translating the roller means across the bore in a direction including a circumferential component while applying a force to the roller means in a radially outwards direction with respect to the longitudinal axis of the pipe, and continuing such translation and force application until the pipe is plastically deformed substantially into the intended profile.
The deformation of the pipe may be accomplished by radial compression of the pipe wall or by circumferential stretching of the pipe wall, or by a combination of such radial compression and circumferential stretching.
Said direction may be purely circumferential, or said direction may partly circumferential and partly, longitudinal.
Said roller means is preferably peripherally profiled to be complementary to the profile into which the selected part of the pipe bore is intended to be formed.
The selected part of the pipe bore may be remote from an open end of the pipe, and the profiling method then comprises the further steps of inserting the roller means into the open end of the pipe (if the roller means is not already in the pipe), and transferring the roller means along the pipe to the selected location. Transfer of the roller means is preferably accomplished by the step of actuating traction means coupled to or forming part of the roller means and effective to apply along-pipe traction forces to the roller means by reaction against parts of the pipe bore adjacent the roller means.
The profiling method according to the first aspect of the present invention can be applied to the profiling of casings and liners deployed in a well (e.g. a hydrocarbon exploration or production well), and the profile created by use of the method may be a liner hanger, or a landing nipple, or another such downhole profile of the type which previously had to be provided by inserting an annular article or mechanism into the well, lowering it the required depth, and there anchoring it (which required either a larger diameter of well for a given through diameter, or a restricted through diameter for a given well diameter, together with the costs and inconvenience of manufacturing and installing the article or mechanism). Additionally or alternatively, the profiling method according to the first aspect of the present invention can be applied to increasing the diameter of a complete length of pipe; for example, where a well has been cased to a certain depth (the casing having a substantially constant diameter), the casing can be extended downwardly by lowering a further length of pipe (of lesser diameter such that it freely passes down the previously installed casing) to a depth where the top of the further length lies a short way into the lower end of the previously installed casing and there expanding the upper end of the further length to form a joint with the lower end of the previously installed casing (e.g. by using the method according to the second aspect of the present invention), followed by circumferential expansion of the remainder of the further length to match the bore of the previously installed casing.
According to a second aspect of the present invention there is provided a conjoining method for conjoining two pipes or other hollow tubular articles, said conjoining method comprising the steps of locating one of the two pipes within and longitudinally overlapping one of the other of the two pipes, applying roller means to a part of the bore of the inner of the two pipes at a location where it is intended that the two pipes be conjoined, translating the roller means across the bore in a direction including a circumferential component while applying a radially outwardly directed force to the roller means, and continuing such translation and force application until the inner pipe is plastically deformed into permanent contact with the outer pipe and is thereby conjoined thereto.
Said deformation may be accomplished by radial compression of the pipe wall or by circumferential stretching of the pipe wall, or by a combination of such radial compression and circumferential stretching.
Said direction may be purely circumferential, or said direction may be partly circumferential and partly longitudinal.
The location where the pipes are intended to be conjoined may be remote from an accessible end of the bore, and the conjoining method then comprises the further steps of inserting the roller means into the accessible end of the bore (if the roller means is not already in the bore), and transferring the roller means to the intended location. Transfer of the roller means is preferably accomplished by the step of actuating traction means coupled to or forming part of the roller means and effective to apply along-bore traction forces to the roller means by reaction against parts of the pipe bore adjacent the roller means.
The conjoining method according to the second aspect of the present invention can be applied to the mutual joining of successive lengths of casing or liner deployed in a well (e.g., a hydrocarbon exploration or production well), such that conventional screw-threaded connectors are not required.
According to third aspect of the present invention, there is provided expansion apparatus for expanding a pipe or other hollow tubular article, such expansion apparatus comprising roller means constructed or adapted for rolling deployment against the bore of the pipe, said roller means comprising at least one set of individual rollers each mounted for rotation about a respective rotation axis which is generally parallel to the longitudinal axis of the apparatus, the rotation axes of said at least one set of rollers being circumferentially distributed around the expansion apparatus and each being radially offset from the longitudinal axis of the expansion apparatus, the expansion apparatus being selectively rotatable around its longitudinal axis.
The rotation axes of said at least one set of rollers may conform to a first regime in which each said rotation axis is substantially parallel to the longitudinal axis of the expansion apparatus in a generally cylindrical configuration, or the rotation axes of said at least one set of rollers may conform to a second regime in which each said rotation axis lies substantially in a respective radial plane including the longitudinal axis of the expansion apparatus and the rotation axes each converge substantially towards a common point substantially on the longitudinal axis of the expansion apparatus in a generally conical configuration, or the rotation axes of said at least one set of rollers may conform to third regime in which each said rotation axis is similarly skewed with respect to the longitudinal axis of the expansion apparatus in a generally helical configuration which may be non-convergent (cylindrical) or convergent (conical). Rollers in said first regime are particularly suited to profiling and finish expansion of pipes and other hollow tubular articles, rollers in said second regime are particularly suited to commencing expansion in, and to flaring of pipes, and other hollow tubular articles, while rollers in said third regime are suited to providing longitudinal traction in addition to such functions of the first or second regimes as are provided by other facets of the roller axes besides skew. The expansion apparatus may have only a single such set of rollers, or the expansion apparatus may have a plurality of such sets of rollers which may conform to two or more of the aforesaid regimes of roller axis alignments; in a particular example where the expansion apparatus has a set of rollers conforming to the second regime located at leading end of the exemplary expansion apparatus and another set of rollers conforming to the first regime located elsewhere on the exemplary expansion apparatus, this exemplary expansion apparatus is particularly suited to expanding complete lengths of hollow tubular casing by reason of the conically disposed leading set of rollers opening up previously unexpended casing and the following set of cylindrically disposed rollers finish-expanding the casing to its intended final diameter; if this exemplary expansion apparatus were modified by the addition of a further set of rollers conforming to third regime with non-convergent axes, this further set of rollers could be utilised for the purpose of applying traction forces to the apparatus by means of the principles described in the present inventor""s previously published PACT patent application W/24728-A, the contents of which are incorporated herein by reference.
The rollers of said expansion apparatus may each be mounted for rotation about its respective rotation axis substantially without freedom of movement along its respective rotation axis, or the rollers may each be mounted for rotation about its respective rotation axis with freedom of movement along its respective rotation axis, preferably within predetermined limits of movement. In the latter case (freedom of along-axis movement within predetermined limits), this is advantageous in the particular case of rollers conforming to the adore-mentioned second regime (i.e. a conical array of rollers) in that the effective maximum outside diameter of the rollers depends on the position of the rollers along the axis of the expansion apparatus and this diameter is thereby effectively variable; this allows relief of radially outwardly directed forces by longitudinally retracting the expansion apparatus to allow the rollers collectively to move longitudinally in the convergent direction and hence collectively to retract radially inwards away from the bore against which they were immediately previously pressing.
According to a fourth aspect of the present invention, there is provided profiling/conjoining apparatus for profiling or conjoining pipes or other hollow tubular articles, said profiling/conjoining apparatus comprising roller means and radical urging means selectively operable to urge the roller means radially outwards of a longitudinal axis of the profiling/conjoining apparatus, the radial urging means causing or allowing the roller means to move radially inwards towards the longitudinal axis of the profiling/conjoining apparatus when the radial urging means is not operated, the roller means comprising a plurality of individual rollers each mounted for rotation about a respective rotation axis which is substantially parallel to the longitudinal axis of the profiling/conjoining apparatus, the rotation axes of the individual rollers being circumferentially distributed around the apparatus and each said rotation axis being radially offset from the longitudinal axis of the profiling/conjoining apparatus, the profiling/conjoining apparatus being selectively rotatable around its longitudinal axis to translate the roller means across the bore of a pipe against which the roller means is being radially urged.
The radial urging means may comprise a respective piston on which each said roller is individually rotatably mounted, each said piston being slidably sealed in a respective radially extending bore formed in a body of the profiling/conjoining apparatus, a radially inner end of each said bore being in fluid communication with fluid pressure supply means selectively pressurisable to operate said radial urging means.
Alternatively, the radial urging means may comprise bi-conical race means upon which each said individual roller rolls in use of the profiling/conjoining apparatus, and separation variation means selectively operable controllably to vary the longitudinal separation of the two conical races of the bi-conical race means whereby correspondingly to vary the radial displacement of each said roller rotation axis from the longitudinal axis of the profiling/conjoining apparatus. The separation variation means may comprise hydraulic linear motor means selectively pressurisable to drive one of said two cones longitudinally towards and/or away from the other said cone.